We've talked about automated iTunes playlist generators before, like MusicIP and The Filter, which purport to create playlists that reflect a certain mood or musical style, etc. In some ways similar, Moody also helps you generate playlists based on mood, however unlike those tools it does not analyze your music or tie into an online database. Instead it requires you to go through your iTunes library tagging your tracks according to mood along two axes: the vertical represents intensity and the horizontal represents happiness. Once your library is mood tagged (with the mood saved in the comments field of the ID3 tags), you can then define playlists (including Smart playlists) based on mood.
The supposed advantage of this method is that your mood tags will be set by you, reflecting your own individual taste, etc. Thus a mood based playlist will more accurately reflect what you think of as intense or happy, etc. rather than some online database. Personally, I think this sounds like an interesting concept, but much like star ratings I don't know if I could get around to tagging enough tracks to make this worthwhile.
Moody is a free download from Crayon Room (donations requested).
[via Cool OSX Apps]